Business has changed. Thanks to the internet, it’s faster and easier than ever to start something of your own. You no longer need to spend a fortune on staff, advertising and premises. You can get something going in 30 days on the side without quitting your job and market it online. Just follow these five steps to make it happen.

1. Find your killer idea

Want to know if a business idea you’ve had is going to work? Then check you can answer “yes” to these three questions. Does this idea excite you? Do you bring something to this idea other than the idea itself (ie skills, knowledge or talents)? Is there demand for this kind of business? If you can’t find any competition, it might be a sign that there isn’t any demand.

2. Do the minimum version

You don’t need a five-year plan. Do what startups do and create a minimum viable product – the smallest version of your business idea that you can put out into the world and prove people like it.

What can you do in 30 days? Get your first client, even if it’s for free. Create your first product. Run your first comedy night or whatever it might be. Did people like it? If so, do it again and make it bigger and better. If people didn’t respond well, find out what was missing and rather than abandoning the whole thing see if there’s a change you could make to fix it.

Think 30 days is not enough? Mark Zuckerberg wrote the first version of Facebook in 30 days and my clients have started successful businesses, from dating profile photography to a historical blog to an international business network, in the same amount of time. They did it by starting small and then growing it.

3. Superniche

It’s hard to move into a crowded market with more experienced competitors. The solution is to “superniche” – focus on a particular kind of person or organisation or create a product or service that’s superb at one particular thing. Be willing to turn people away and you’ll make yourself irresistible to the right kind of person.

4. Get your first customer

Skip the fancy logo and elaborate website. Put your focus on getting your first customer or client. If you can get one, you stand a good chance of being able to get 10 and if you can get 10 you stand a good chance of making the business work.

If you need a website, create a one-page website on a system like Strikingly in an hour or two. Now is not the time to worry about how to get a million visitors to your website. Win your first client or customer from within your own network – reach out to your social and business circles and explain the value you or your product provides and get your first sales.

5. Do a back-of-an-envelope business plan

Forget writing a complex business plan. If you follow these guidelines to start without large expenditure you don’t need one but it is worth doing a rough calculation. What’s your target annual income? Given the price you’re intending to charge and any costs you have, how many clients or sales would you need to hit that target? Divide it by 52 and check you can actually sell and deliver that many sales in a week. Bear in mind that you should be able to find ways to increase your prices over time.

What’s the minimum you can survive on in a month? When you can make that from your new business, you might be ready to quit your job.

Screw Work, Break Free, by John Williams, is out now on Vermilion. Williams will be talking at Penguin Living careers 360 on 11 September.

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